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Biomedical subjects

I Cooper

Publications and source records attributed to I Cooper.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Migration studies on fatty acid amide slip additives from plastics into food simulants.

Specific migration studies, using food simulants, have been conducted on a range of polymers which are used in food packaging and contain commonly used fatty acid amide slip additives. Migration levels using the test conditions (10 days at 40 degrees C) were found to depend primarily upon the food simulant and the polymer type, with the fat simulant and low density polyethylene giving the highest values in the range 1.8-3.1 milligrams of fatty acid amide per kilogram of simulant. Extremely low levels of migration, < 0.05 milligrams of fatty acid amide per kilogram of simulant, were found with aqueous food simulants for all plastics tested, and fat simulant with PVC and polystyrene plastics.

Amides↗
PubMedDate not supplied

Hydrolysis studies on oleamide in simulated gastrointestinal fluids.

Hydrolysis studies using simulated gastrointestinal fluids have been performed on oleamide, an important fatty acid amide slip additive used in plastics food packaging. Experiments have been conducted using the simulated gastrointestinal fluids, specified by the Scientific Committee for Food for hydrolysis studies, and with slightly modified preparations believed to be more representative of the in vivo situation. The degree of hydrolysis in simulated gastric fluids was found to be negligible after incubation for 4 h at 37 degrees C. Addition of 'bile salts' to simulated intestinal fluid was found to significantly increase the degree of hydrolysis to about 95% loss of oleamide after incubation for 4 h at 37 degrees C. Stoichiometric formation of oleic acid, an innocuous substance, was also demonstrated. It has therefore been concluded that ingestion of the very low levels of oleamide expected to migrate into most foods from food packaging is unlikely to pose a threat to the health of the consumer.

Bile Acids and Salts↗
PubMedDate not supplied

Correlation of specific migration (Cf) of plastics additives with their initial concentration in the polymer (Cp).

The first list of plastics additives which may be assigned restrictions in a future amendment to Directive 90/128/ EEC is likely to contain over 200 substances. If food consumption factors are taken into account many compounds on this list could have restrictions removed but there would, without doubt, still be many additives with restrictions. Extensive migration testing of food contact plastics containing restricted additives to ensure compliance would be required. These limits would be difficult to enforce, add significant cost burdens on the packaging industry and, for these reasons, may not provide improved consumer safeguards. An alternative means of control has been proposed based upon polymer composition. However, in order to support such a scheme a reliable correlation between migration of additives to their composition in the polymer must be demonstrated. There has been strong interest in establishing this relationship and a feasibility project to investigate the specific migration of four commonly used additives has been successfully completed. The study was initially funded for 1 year, by the Ministry of Agriculture, Fisheries and Food (MAFF) and industry. Analytical methods to determine the additives in food simulants have been developed and linear correlations have been demonstrated between the concentration of all four additives and their specific migration levels for each polymer studied. Experimental migration data have been compared with those generated by mathematical models.

Diffusion↗
PubMedDate not supplied

Activity of twenty-one antimicrobial agents including l-ofloxacin against quinolone-sensitive and -resistant, and methicillin-sensitive and -resistant Staphylococcus aureus.

There is a need to identify alternative agents to vancomycin for the treatment of infections with methicillin-resistant Staphylococcus aureus (MRSA). One candidate is the l isomer of ofloxacin (DR-3355). We tested 520 frozen MRSA isolates, 248 fresh MRSA isolates, and 375 fresh methicillin-susceptible S. aureus (MSSA) isolates from Minnesota, and 600 clinical isolates of S. aureus (150 MRSA and 450 MSSA) from Illinois. Over 90% of the MRSA strains were resistant to 32 micrograms/ml of oxacillin. Of the 520 frozen MRSA, 24% were susceptible to < or = 2 micrograms/ml ofloxacin, and an additional 74% were susceptible to ofloxacin between 8 and 16 micrograms/ml. More than 98% of all strains were susceptible to < or = 16 micrograms/ml ofloxacin or l-ofloxacin. All the quinolones had a bimodal distribution of in vitro activity, but for only ofloxacin and l-ofloxacin was activity confined to a very narrow range.

Anti-Bacterial Agents↗